Wikipedia
Arbacioida
The Arbacioida are an order of sea urchins, consisting of a single family, the Arbaciidae. They are distinguished from other sea urchins by the presence of five separate plates around the anus. Unlike their close relatives, the Salenioida, all of the tubercles on their tests are of similar size. It contains these genera:
- Arbacia Gray, 1835
- Arbaciella Mortensen, 1910a
- Arbia Cooke, 1948†
- Baueria Noetling, 1885†
- Codiopsis L. Agassiz, in Agassiz & Desor, 1846†
- Coelopleurus L. Agassiz, 1840a
- Cottaldia Desor, 1856 †
- Dialithocidaris A. Agassiz, 1898
- Habrocidaris A. Agassiz & Clark, 1907b
- Podocidaris A. Agassiz, 1869
- Pygmaeocidaris Döderlein, 1905
- Sexpyga Shigei, 1975
- Tetrapygus L. Agassiz, 1841b